M Factory Limited Slip with 3.46 – Anyone do this one?

[383backinblack]

Has anyone done this exact swap? (Driving a 2011 135i 6MT)

Is there any tuning required when changing the gear ratio on these cars? (I'm still sort of new to the platform, but I've been lurking/lusting for years).

The car currently has a VRSF charge pipe, down pipe, and a bigger IC with an MHD stage 2+ tune and it RIPS. First gear is pretty short already, so I'm curious if it's worth going with the 3.46 gear over the factory 3.08, too.

[scratchgolf135]

I can see this on a 128i but on anything above stock power levels I can’t imaging how 3.46 would be useful. Traction is already an issue (will be even with LSD, I assure you). I’m single turbo now and almost considered going the opposite direction with gearing when I had my Wavetrac installed as even at .9 bar wastegate spring traction is going to be non-existent in first and likely second.

[383backinblack]

Originally Posted by scratchgolf135

I can see this on a 128i but on anything above stock power levels I can’t imaging how 3.46 would be useful. Traction is already an issue (will be even with LSD, I assure you). I’m single turbo now and almost considered going the opposite direction with gearing when I had my Wavetrac installed as even at .9 bar wastegate spring traction is going to be non-existent in first and likely second.

Doing sick burnouts and leaving fat stripes is not a bug, it's a feature haha ...
Glad to hear that perspective ... I'm looking to eventually be at about 400hp (once I get around to a bigger turbo).

[scratchgolf135]

Originally Posted by 383backinblack

Doing sick burnouts and leaving fat stripes is not a bug, it's a feature haha ...
Glad to hear that perspective ... I'm looking to eventually be at about 400hp (once I get around to a bigger turbo).

Sure you’re not already at that power level? I would assume you’re close with yours hardware and tune. Obviously 3.46 would be utterly useless for me at 750whp.

[xrockoutx]

I've got an OS Giken and 3.46's with Pure Stage 2 (n55). It's not bad...but I'm always on 200 tw tires. The gearing kind of threw off the groove for our local auto-x setup though, so now I'm always in a weird spot...think about the gearing and what you want out of the car. For drifting it's spot on...just made grip events awkward.

[383backinblack]

Originally Posted by scratchgolf135

Sure you’re not already at that power level? I would assume you’re close with yours hardware and tune. Obviously 3.46 would be utterly useless for me at 750whp.

It feels fast AF, but I haven't seen anyone claiming to hit 400whp with the same setup. I've read a few posts from tuners like wedge and the MHD guys saying it's a real stretch with a stock turbo, but with one, no problem. E85 would be a different ball game of course.

750hp must be utterly useless in one of these cars lol ... my Camaro is about 1,000hp, (also utterly useless on the street) and a lot heavier/bigger, so I'd assume they feel similar.

[383backinblack]

Originally Posted by xrockoutx

I've got an OS Giken and 3.46's with Pure Stage 2 (n55). It's not bad...but I'm always on 200 tw tires. The gearing kind of threw off the groove for our local auto-x setup though, so now I'm always in a weird spot...think about the gearing and what you want out of the car. For drifting it's spot on...just made grip events awkward.

Good to know ... I would like to get it to some track days in the not too distant future, but I will be daily driving it as well. Def don't want to upset the gearing (it's honestly not bad as-is). I don't have any plans to try to max it out for drag racing (have a different car for that).

[PRTSB1M]

With 25" tires (18" wheels) 3.46 is probably too short. F8x M cars come with 3.462 and the same transmission gear ratios as 6spd N55 cars; however, they also come on 26" tires (19" wheels) and have a higher RPM limit (power band).

[383backinblack]

Originally Posted by PRTSB1M

With 25" tires (18" wheels) 3.46 is probably too short. F8x M cars come with 3.462 and the same transmission gear ratios as 6spd N55 cars; however, they also come on 26" tires (19" wheels) and have a higher RPM limit (power band).

Ahh thanks ... great info. I'm going to get wheels for this thing, but likely sticking with 18s so I'll stay with the 3.08s.

[AshwinLB]

I have 3.46 mfactory LSD on my 2008 135i manual (265/35R18). I can see how people find it too short but for me it livened up the car alot in pre-boost situations. It’s most likely a little slower due to needing to shift more often but feels faster. I definitely don’t regret it but would probably go to a 3.31 ratio if I do a Ford 8.8 LSD conversion to get the best of both

[383backinblack]

Originally Posted by AshwinLB

I have 3.46 mfactory LSD on my 2008 135i manual (265/35R18). I can see how people find it too short but for me it livened up the car alot in pre-boost situations. It’s most likely a little slower due to needing to shift more often but feels faster. I definitely don’t regret it but would probably go to a 3.31 ratio if I do a Ford 8.8 LSD conversion to get the best of both

Oh nice, how long have you had it? Do you remember how much fluid it took (I've had no luck finding the fluid capacity anywhere so far).

I've got the diff (with a 3.08) on the way now (the car already feels fast AF, and I have a 1,000hp drag car with 4.11s anyway haha) along with the Dinan short throw shifter. I'm REALLY looking forward to installing this thing!

[AshwinLB]

Originally Posted by 383backinblack

Oh nice, how long have you had it? Do you remember how much fluid it took (I've had no luck finding the fluid capacity anywhere so far).

I've got the diff (with a 3.08) on the way now (the car already feels fast AF, and I have a 1,000hp drag car with 4.11s anyway haha) along with the Dinan short throw shifter. I'm REALLY looking forward to installing this thing!

I installed it onto the car last May! Although I did buy the helical unit a little more than a year before but got frustrated/lazy with putting it into the stock auto diff from a 2007 335i (still large case and bolted for this model year)

With the large case diff it took around 1.5q so 2 bottles of redline fluid will definitely be enough. (Although there is break-in so I bought 4 bottles)

Wow you will definitely enjoy it with that monster of setup you got going!! I’m just FBO with an RTD shifter and it made a world of a difference in grip and fun

[383backinblack]

Originally Posted by AshwinLB

I installed it onto the car last May! Although I did buy the helical unit a little more than a year before but got frustrated/lazy with putting it into the stock auto diff from a 2007 335i (still large case and bolted for this model year)

With the large case diff it took around 1.5q so 2 bottles of redline fluid will definitely be enough. (Although there is break-in so I bought 4 bottles)

Wow you will definitely enjoy it with that monster of setup you got going!! I’m just FBO with an RTD shifter and it made a world of a difference in grip and fun

Awesome thanks! I've had this camaro in profile photo for over 20yrs ... it's got a supercharged 383 in it that makes a little over 1,000hp. Honestly, the 135 is WAY more fun to drive on the street because you can WAIL on it. Having been on the HP journey for a long time, and well into 4-digit territory, I have no plans to care about the bimmer making more than 400ish hp. After that, it's just faster wheel spin and more noise outside of a prepped track anyway

[Wegz]

I have the MFactory 3.46 on my 2013 6MT car. You are gonna have a ton of midrange and can lug in just about any gear. The stock turbo runs out of steam around 5500 though.

I'm looking at going with the Shuenk turbo upgrade to get this bitch pulling to and past 7000RPM

[BruceThomas]

Hey Guys,

2011 135 - 6 MT - PS2 roughly 400 WHP

After much deliberation I to have decided to go for the 3.46 MFactory helical LSD.

There are pros and cons to staying 3.08 and/or going 3.46

I decided to go 3.46 because, I use the car exclusively for canyon driving and currently, the car is off boost too much of the time.

Initially I had a tune that SUCKED. Even to the point that I regretted putting the PS2 on. As Wegz said, I put the PS2 on to get a much bigger and usable power band. But the car was so laggy and would take forever to hit boost. Thankfully worked with one of the guys from on here and he got me boosting much earlier and way more linear. However, the car can still drop out of boost if you don't keep the RPM and momentum going.

So decided to give 3.46 a try. My concern could be running out of gear too much, and it being counterproductive to my initial PS2 goal of giving the car a longer power band. But it could be the lesser of two issues: late spool or shorter power band.

If tracking the car, 3.46 would seem almost a necessity, especially if running an upgraded turbo/s.

LSD is being fitted on Monday. I will share feedback over the next few weeks.

Thanks

[wheela]

Originally Posted by BruceThomas

Hey Guys,

2011 135 - 6 MT - PS2 roughly 400 WHP

After much deliberation I to have decided to go for the 3.46 MFactory helical LSD.

There are pros and cons to staying 3.08 and/or going 3.46

I decided to go 3.46 because, I use the car exclusively for canyon driving and currently, the car is off boost too much of the time.

Initially I had a tune that SUCKED. Even to the point that I regretted putting the PS2 on. As Wegz said, I put the PS2 on to get a much bigger and usable power band. But the car was so laggy and would take forever to hit boost. Thankfully worked with one of the guys from on here and he got me boosting much earlier and way more linear. However, the car can still drop out of boost if you don't keep the RPM and momentum going.

So decided to give 3.46 a try. My concern could be running out of gear too much, and it being counterproductive to my initial PS2 goal of giving the car a longer power band. But it could be the lesser of two issues: late spool or shorter power band.

If tracking the car, 3.46 would seem almost a necessity, especially if running an upgraded turbo/s.

LSD is being fitted on Monday. I will share feedback over the next few weeks.

Thanks

Rather than update the diff, have you considered going to the new pure750? Supposedly it spools sooner than ps2 and flows more up top. But I haven't seen anybody with one post about it yet. Sorry op if this is meandering a little off topic, just thought it related since he's considering a diff change.

[wheela]

Glad you're enjoying your 135, I currently have basically the same mods on my e84 - I can't imagine what a car with over 1000hp would feel like!

[ShocknAwe]

If you have enough torque (big twins etc) a 3.46 turns a 135i trans into a dog leg 5 speed. I almost never use first anymore.

[Yert315]

I have a 3.46lsd in mine with stock turbos and a mild tune. I think this gearing is perfect for an oem+ car. If you drive highways often it’s probably not the best but will be plenty fun!

[383backinblack]

Love all the different experiences and applications here ... I've had the M Factory LSD with 3.08s in the car for about 2 weeks now, and so far it's great ... it's so satisfying to get that tail wag on throttle coming through a corner when it starts to rotate

A few hundred miles to go to change the break in oil out!

[PRTSB1M]

Originally Posted by 383backinblack

Love all the different experiences and applications here ... I've had the M Factory LSD with 3.08s in the car for about 2 weeks now, and so far it's great ... it's so satisfying to get that tail wag on throttle coming through a corner when it starts to rotate

A few hundred miles to go to change the break in oil out!

LSD is definitely what the E82 is missing. Glad you're driving it proper

[383backinblack]

Originally Posted by PRTSB1M

LSD is definitely what the E82 is missing. Glad you're driving it proper

This car inspires hoonery in a way no other car I've owner has (including the Camaro). It's definitely going to get my in trouble ... and as a bonus, it gets 23mph when you're driving it like a dink